1. Field of the Invention
The present invention relates to electrical card connectors, more particularly to electrical card connectors with improved card restriction structure for restricting and guiding insertion of corresponding cards.
2. Description of Related Art
Nowadays, memory cards are widely used in electronic devices. There are many kinds of memory cards such as MMC (Multi Media) card, SD (Secure Digital) card, xD (xD-Picture) card, MS (Memory Stick) card and MS (Memory Stick) Duo card. According to the standard specification, the dimension of the MS card is 50 mm×21.5 mm×2.8 mm and the dimension of the MS Duo card is 31 mm×20 mm×1.6 mm. It is obvious that the MS card is much wider and thicker than the MS Duo card.
Electrical card connectors are usually mounted on a PCB of the electronic devices to establish data transmission between the memory cards and the electronic devices. It is a common knowledge to those of ordinary skill in the art to know that both the MS card and the MS Duo card are compatible to a MS card connector or a multiple-in-one card connector having MS card contacts disclosed in U.S. Pat. No. 6,994,574. Such card connectors only defines a wide slot for guiding insertion of the MS card. However, when the MS Duo card is inserted along the slot, it may be rock along a left-to-right direction because the MS Duo card is much narrower than the MS card. As a results, signal transmission is terribly affected.
Hence, an improved electrical card connector with improved card restriction structure is needed to solve the problem above.